Mobile communication systems have been developed to provide the subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services as well as the standard voice communication services. However, the resource shortage and user requirement for higher speed data services spur the evolution of the mobile communication system to more advanced system.
In order to meet such requirements, the 3rd Generation Partnership Project (3GPP) has developed Long Term Evolution (LTE) as one of the promising next generation mobile communication systems. LTE is a technology designed to provide high speed packet-based communication of up to 100 Mbps and aims at commercial deployment around 2010 timeframe. In order to accomplish the aim, a discussion is being held on several schemes: one scheme for reducing the number of nodes located in a communication path by simplifying a configuration of the network, and another scheme for maximally approximating wireless protocols to wireless channels.
A Multiple Input Multiple Output (MIMO) wireless communication system supports Multiuser-MIMO (MU-MIMO) mode for increasing system throughput. Particularly, the LTE-Advanced (LTE-A) is designed to support up to 8 layers transmission.
The data streams of up to 8 layers are allocated to the users depending on the per-user channel conditions and scheduling scheme in Single User MIMO (SU-MIMO) and MU-MIMO modes.